Teracube 2e (2nd batch; SN:2021) screen going dark during calls

Hello! I got a teracube 2 last month, and have been having the same problem: immediately when I make or accept a call, the screen goes dark and the buttons are unresponsive. This continues until the call is ended, which I cant do myself because of the locked screen, so the other person must hang up. This becomes more of an issue if I am connected to a robocall or phone tree that does not hang up.
I think the problem is not based on a software issue but based on the factory-installed screen protector triggering the proximity sensor. I have discovered two workarounds:

  1. I’d you press your thumb briefly against the proximity sensor and release, the screen unlocks.
  2. If you plug in headphones into the jack, the phone unlocks (I assume because the proximity sensor is not used during calls with headphones)
1 Like

Possibly dumb question, but on the T2e, where exactly is the proximity sensor? Is it between the front-facing camera and LED indicator (white when charging)?

Hi @Jcbohnhoff - welcome to Teracube forums. That does seem like a screen protector issue. Could you try the following:

  1. Try cleaning the area between the earpiece at the top and the notification led. you can use an alcohol wipe. @PlantProtein86 - you are correct about the location.
  2. If cleaning does not work, then I’ll suggest you can remove the screen protector and either re-install it after cleaning it from the back. Or we can ship you another screen protector.

I’m not concretebox but am a new user and having the issue so figured I’d respond with a description (apologies to @concretebox for potential thread jacking)

  1. Device type?
    T2e (2022 edition)

  2. what exactly is the issue?
    While on a phone call, transition from vertical ear talking position to off-ear horizontal (typically to end the phone call) the screen remains off.
    Unable to ‘wake up’ the screen

  • side button presses of any of the three buttons don’t change anything
  • Finger print sensor touches doesn’t have any effect.

Most of the time, the phone call has to be terminated by the network side before screen turns on.

‘Most of the time’ because it seems the duration in the vertical ear talk position makes a difference. If it’s short- a few seconds- a transition from vertical talk to horizontal will result in the expected behavior (screen turns on, can end call, switch apps, etc…) but it seems my typical duration (no answer-> leave voicemail → try to end call) results in screen being off until the network terminates the call.

  1. do you have a screen protector on the phone
    Only the factory-installed protector (haven’t messed with anything)

4.Your OS version.

Hi @PlantProtein86 - could you please try the suggestions mentioned above (link).

I feel a little dumb, but cleaning seems to do the trick for my T2e-2022. There was a lot of dust/lint underneath the top edge of the screen protector and definitely was covering the sensor.

Once cleaned, behavior was as expected (screen turns off ‘on ear’ and turns back on when off ear)

Will now need to figure out how to keep that area clean but at least mystery is no longer a mystery. Thank you!



Removing the screen protector and cleaning it and the sensor area worked like a charm! Thanks!


2 posts were split to a new topic: Screen going dark due to screen protector

I have the same issue which I assume is due to the screen protector: the screen stays black and no buttons cause any action during a call or for a (long) while after. (This makes it impossible to select a number when calling a call center!)
I suspect that the face sensor is being blocked by pocket lint! I measured with a feeler guage from the top and there is a slot for said pocket lint to accumulate that is about 0.25 mm wide between the protector and the sensor, which extends to the right over the LED as well.

Yeah - it seems our new screen protectors are overprotective. This old design is probably the best. Also the 3rd party ones are also better even though they result in a thin air gap on the right side.

Something to improve on in our next production run.

1 Like

I, too, am running into this issue.
I will see if i can press the sensor to allow the screen to work again or cleaning it. Otherwise I will have to remove the screen protector (which i’d prefer to not have to do), but how well.

Take a toothpick and whittle it down to a fine point, and use that to clean out the space behind the screen over the sensor.

This has been happening to me too. I was a bit worried my recently acquired 2e was faulty. It was a big relief when I cleaned the screen and it seems to have resolved the problem. So glad I found this topic. Many thanks for the info and for the remedy! :blush:

1 Like

I also had this problem, cleaning the relevant area fixed it - I laughed at how simple it was! However, I removed the screen protector which seemed rather tacky on the inside. I tried gently cleaning with a soft cloth but it now looks rather grubby and doesn’t adhere properly to the screen. It’s functional, but isn’t great. How do I clean the underside of the screen protector, or do I need a new one?


1 Like


It depends! If you’ve damaged the (very fragile) underside, it won’t ever be right again. You can try washing it with warm soapy water (powerful dish soap is best) to help remove oils from your handling, dust, dirt, etc, but this is not likely to be successful.

Thanks for the response. It isn’t damaged, and I didn’t make it dirty in handling it when I removed it (for the first time, as it arrived pre-installed). It came off noticeably sticky or tacky, as if that is how it was originally applied to the phone. Never had that with screen protectors I’ve bought for other phones. Are the screen protectors that come included typically like this? It definitely wasn’t a bit of grease or dust from handling and use, it was a noticeably sticky surface all over the underside.

1 Like

Yeah, that’s normal. These glass screen protectors use a mild tacky adhesive layer and static on the underside to bond with the screen.

1 Like